f(x+h)-f(x) / h Where f is a given function of x and h is a number. How do I find the difference quotient for f(x)= 4x^2-3x?

4 (x + h)² - 3 (x + h) - [ 4x² - 3x ]
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h

4 x² + 8hx + 4h² - 3x - 3h - 4x² + 3x
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h

8 hx + 4h² - 3h
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h

8x + 4h - 3

f ` (x) = 8x - 3
h